Portable burglar-alarm.



E. S. BROOKS.

PORTABLE BURGLAR ALARM.

APPLICATION FILED SEPT. 1. 1916.

1,287,627. Patented Dec. 17, 1918.

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EMERSON s. BROOKS, or sAN FRANCISCO, CALIFORNIA. 7

PORTABLE BURGLAR-ALARM.

' Specification of Letters Patent. Patented Dec. 17, 1918.

Application filed September 7, 1916..- Serial No. 118,887.

To all whom it may concern Be it known that I, EMERSON S. BRooKs, a citizen'of the United States, residing at San Francisco, in the county of SanFrancisco andState of California, have invented 7 new and useful Improvements in Portable Burglar-Alarms, of which the following is a specification. r

This invention relates to a portable bur glar alarm, especially designed for use by travelers and others to be employedfor giving an alarm when a door or window is surreptitiously opened, the object of the invention being to provide :1 portable alarm Which is simple in construction, inexpensive Of production, capable of being carried in the pocket or in an ordinary traveling bag, and which is positive in action in giving an audible alarm when the door or window in conjunction withwhich it is used is opened.

A further object of the invention is to provide a portable burglar alarm of the detonating type which is-adapted for use in connection with ordinary explosive caps, and

which embodies a pivotally mounted hammer for detonating the caps, said hammer being adapted to be tripped for action by the opening movement of the door or window and to be thrown into action through the medium of an actuating spring, whereby a positive firing action will be insured.

A still further object of the invention is to provide a form of spring and coacting cam upon the hammer, which cam and spring are adapted for cooperation tohold the hammer against accidental release in set position, to limit the movement of the hammer when retracted beyond a set position, and to positively throw the hammer into operation when tripped for action.

With the above and other objects in View, the invention Consists in the features of construction and the combination and arrangement of parts which will be hereinafter described, defined in the appended claim and illustrated in the accompanying drawings, in which: v

Figure 1 is a perspective view showing the mode of use of the invention;

Fig. 2 is a longitudinal section showing the hammer in folded position;

Fig. 3 is a similar view showing in full and dotted lines different positions to which the hammer may be set for action;

Fig. 4 is a detail perspective view of the hammer.

.ward and rearward direction.

1 In carrying my invention into practice, I provide a portable alarm device comprising a body or baseplate 1, preferably; of oblong rectangular form, and provided upon its under side, adjacent to its rear end, with a holding device 2 in the form of a pin or spur, for securing the alarm in position for use. At its Opposite or forward end the plate 1 is provided with a bed or anvil surface 8 serving as a support for the cap 1 to be detonated, above whichsurface 3 is arranged a horizontal guide plate 5 supported from the plate by a vertical transverse flange 6, said guide plate 5 being provided with a guide opening 7 for the passage of. the firing pin 8 in its movement toward theanvil for the purpose of setting ofi the cap. The firing pin 8 is'mounted upon the'free end of a hammer 9. This hammer 9 comprises an armor bar pivotally mounted at I its opposite end upon the pin or rivet 10 passing through a pair of parallel upright lugs 11 extending upwardly from the rear end of the plate 1, whereby the hammer is adapted for movement from a normally upright cooked or set position to a horizontal position parallel with the plate for a firing action, and vice versa. The device constructed as thus described is of convenient form to be carried in the pocket or in a I traveling bag or similar article.

Secured at its forward end to the plate 1 is a plate or ribbon spring 12, the rear end 13 of which extends between and beyond the lugs 11, the said rear end 13 of the spring being arcuately curved in an up- This end of the spring is arranged for cooperation with a cam member 1 1 upon the pivoted end of the hammer 9, said cam member forming a friction shoe having a curved surface 15 for engagement with the curved end of the spring, a flat surface 16 substantially parallel with the arm, and a short fiattoe por-' ,tion 16 at the point of intersection of the surfaces 15 and 16. The toe portion 16 is disposed at an oblique upward and rearward angle to the plane of the arm for engagement with the curved end of the spring,

as shown in full lines in Fig. 3, to hold the hammer arm in the inclined set position shown in Fig. '3, in which the arm lies slightly in rear of its pivot pin or fulcrum 10 at an Obliqueangle to the perpendicular. The fiat stop surface 16 is adapted to engage the upturned rear edge of the spring to positively limit the rearward movement of the hammer to a degree beyond a normal or primary upright cocked position so as to )revent the hammer from movin backward in primary set position for a maximum binding action to hold the hammer in such position against casual displacement, but not to such a degree as to prevent the hammer from being forced forward and positively thrown for a firing action by the pressure of the spring when the hammer is moved forward to a predetermined degree. When the hammer is moved forward to a point beyond center the curved end of the spring, engaging the toe or point of the cam, quickly throws the hammer to a firing position to effect the setting off of the cap.

In the use of the device, the plate 1 is rested against the floor or threshold or against a portion of a window frame so that the hammer 9, when set, will lie in the path of opening movement of the door or window sash, the spur 2 being embedded in the woodwork to hold the alarm in position.

The cap 4; is then placed upon the anvil surface 3, with its explosive charge in line with the opening 7 so that when the door or window is opened to any appreciable degree and contacts with and moves the hammer 9 to a released position the spring 12 will actuate the hammer on its firing operation, the pin 8 passing through the opening 7, and being thereby guided to accurately strike the center of the cap to positively fire the same. By this means a warning will be given of the entrance or attempted entrance of an intruder. It will be observed that the guide plate 5 forms, in conjunction with the anvil surface 3, a cap receiving or firing chamber which is open on three sldes for the ready and convenient entrance of the cap, and that said plate serves to frictionally engage the cap to maintain it in position, allowing the device to be employed either horizontally or vertically without liability of. the cap becoming displaced by gravity, shocks or jars or other accidental causes.

The flat stop surface 16 is adapted to engage the upturned rear end of the spring, as shown in dotted lines in Fig. 8, to permit the hammer or striker arm 9 to be swung rearwardly beyond its pivot to a secondary cooked or set position in which it is horizontally disposed or lies in a plane parallel with and'in advance of the base plate 1. In setting the hammer arm from the firing position shown in Fig. 2 to the primary or normal upright cocked position, shown in Fig. 1 and in full lines in Fig. 3, the curved end 13 of the spring, when engaged with the intermediate contact surface 16, will, owing to the angle of inclination of said surface 16, resist any further backward movement of the hammer arm. As a result the hammer arm may be swung back of the primary cocked position to a certain extent without disengagementof the surface 16 from the spring, since the curved end of the spring may yield and remain in contact with the surface 16 while allowing 6 the surface 16 to contact with the projecting extremity of the spring in which action the said surface 16 and extremity of the spring serve as stops to prevent rearward movement of the hammer arm to such an extent as to cause the surface 16 to swing forward to a point in advance of the vertical plane of the pivot 10, except when an abnormal degree of force or pressure on the hammer arm is exerted. By, however, swinging the hammer arm' backward with excessive (abnormal) force or pressure the point 16 will be carried forward sufficiently to release it from engagement with the spring, allowing the surface 16 to contact fully with the free end of the spring and the hammer arm to assume and be held in the backward secondary cocked or set position shown in dotted lines shown in Fig. 3. Thus the hammer arm may be cooked or Set in two operative positions, in one of which it stands substantially at right angles or perpendicularly to the plane of the base plate, and in the other of which it extends in advance of and parallel with the plane of the base plate. The stop action referred to is to prevent the hammer arm from passing casually beyond the primary to the secondary cocked position when it is intended to be set and held'in the primary position. The purpose and mode of use of the device with the hammer arm set in the primary cocked position has been fully illustrated and described. The hammer arm may be placed in the secondary cocked position for use in cases where the base plate may be secured to a frame or casement parallel with the plane of a door or window mounted to swing at right angles thereto, and in which the hammer arm, when so disposed, will project into the path of swinging move ment of the door or window, the construction of the device thus being such that the base plate may be disposed at right angles to or in the same plane as the door or other closure, as different conditions of use may require.

It will be observed that when the hammer is set in the rearwardly inclined position shown in Fig. 3 the toe portion 16 coacts with the spring to transmit the pressure falling upon the hammer from the opening door to the adjacent end of the base plate, and that this pressure is maintained thereafter by contact of the cam surface 15 with the spring as the hammer falls. By this means the pin is kept forced into the floor and its accidental disengagement prevented during the actuation of the alarm. Also it will be observed that when the hammer is disposed parallel with the base plate 1, as shown in Fig. 2, the Hat face 16 is disposed horizontally above the pivoted terminal of the hammer and forms an anvil to receive the blows of a hammer, whereby the pin may be driven into the floor.

Having thus described my invention, I claim:

A portable burglar alarm including an elongated base plate, a pointed floor penetrating pin projecting at right angles from and adjacent one end of the plate, a detonating cap holder carried by the opposite end of said plate, a door engaging hammer pivotally secured to the pin carrying terminal of the plate and provided at one end with a firing pin for engaging the cap in said holder and at its opposite end with a cam, a spring secured at one end to said plate and engaged at its opposite end with said cam to throw said hammer toward the holder, said hammer having a fiat toe portion arranged to coact With the spring and retain said hammer in an outwardly inclined position with relation to said plate, whereby pressure exerted upon the hammer by an opening door serves to force said pin into the floor and anchor the plate in position, and an anvil carried by the pivoted terminal of the hammer and adapted when swung to a position overlying said pin to be struck to drive the latter.

In testimony whereof I afiix my signature in presence of a witness.

EMERSON S. BROOKS. Witness:

BENNETT S. Jonns.

Copies of this patent may be obtained for five cents each, by addressing the commissioner of Patents,

Washington, D. 0." 

